- Hip replacement: For calculation of the number of patients we aim to see a significant difference of at least 20% better wound healing after use of fibrin sealant during surgery. From a pilot we observed for wound healing a score of 1.58±0.79. With the power at 80% and alpha at 0.05 we need 96 evaluable patients in both study group (fibrin sealant treated) and control group (non fibrin sealant treated).